Fluid delivery system for aircraft windshields

ABSTRACT

A fluid delivery system useful for delivery of rain repellent fluid to aircraft windshields including first and second tanks of fluid under pressure, a valve to control first tank delivery to a discharge line and adapted to close when discharge line pressure is greater than the first tank pressure and means responsive to first and second tank pressure, e.g., to a predetermined ratio of such tank pressures to control second tank discharge to the line.

Unite ttes Feet Schiller [451 Mar. 7, 1972 [54] FLUID DELIVERY SYSTEMFOR AIRCRAFT WHNDSHIIELDS [72] Inventor: Teddy Ml. Schiller, HuntingtonBeach,

Calif.

[73] Assignee: Purex Corporation, Ltd., Lakewood, Calif.

[22] Filed: June 5, 1970 [21] Appl. No.: 43,859

[52] US. Cl ..244/121 [51] Int. Cl ..B64c 1/14 [58] Field oiSenrch..244/121; 137/113 [56] References Cited UNITED STATES PATENTS 3,131,7085/1964 Knight ...l37/113 3,513,751 5/1970 Escobosa ..137/1l3 PPESSUP/ZEDFLU/D 3 SUPPLY #2 3,550,613 12/1970 Barber ..137/113 3,559,928 2/1971Dohmeyer 2,849,760 9/1958 Boeke et a1 ..244/12l Primary ExaminerMiltonBuchler Assistant Examiner-Steven W. Weinrieb Attorney-White, Haefligerand Bachand [5 7] ABSTRACT A fluid delivery system useful for deliveryof rain repellent fluid to aircraft Windshields including first andsecond tanks of fluid under pressure, a valve to control first tankdelivery to a discharge line and adapted to close when discharge linepressure is greater than the first tank pressure and means responsive tofirst and second tank pressure, e.g., to a predetermined ratio of suchtank pressures to control second tank discharge to the line.

8 Claims, 3 Drawing Figures PREsa'L/P/zED F L L/ID auppu /2 FLU/DUTILIZATION DEV/CE SOLENOID VALVE CONTQOL 50.

FLUID DELIVERY SYSTEM FOR AIRCRAFT WINIJSIIIELIDS BACKGROUND OF THEINVENTION 1. Field of the Invention This invention has to do with asystem for alternate delivery of fluid from self-pressurized tanks to afluid utilization device in a predetermined manner providing adequatepressure at the device for effective use during service periods. In aparticular aspect, the invention is concerned with regulating thedelivery of rain repellent fluid to aircraft Windshields from one of twoself-pressurized tanks in an alternate manner dependent on the ratio ofpressures between the two tanks and independent of the discharge linepressure.

2. Description of the Prior Art The regulation of fluid flow fromself-pressurized containers, or tanks, with check valves responsive totheir respective containers and discharge line pressure is known. In thepast, however, these expedients, particularly as utilized in theaircraft windshield rain repellent field have alternated or combinedfluid supply to the windshield and continued operation has sometimesresulted in unknowingly badly depleted supplies, and thus suddenlyinadequate fluid pressures for effective application to the windshield.

SUMMARY OF THE INVENTION It is a major objective of the presentinvention to provide a fluid delivery system in which fluid deliveryfrom a second tank supply is controlled by means responsive to pressurein the first tank and pressure in the second tank, and particularly to apredetermined ratio of second tank fluid pressure to first tank fluidpressure.

Accordingly, the invention contemplates a fluid delivery systemincluding a first tank of fluid under pressure, a valve to control firsttank delivery to a discharge line and adapted to close when dischargeline pressure is greater than the first tank pressure, and meansresponsive to first tank pressure to control second tank discharge tothe line. In general, the last mentioned means includes valve meansresponsive to second tank pressure relatively higher than first tankpressure to permit second tank discharge into the line and independentof discharge line pressure. The valve means may include a valve memberand means communicating first tank fluid pressure to the valve membersuch as a fluid receiving bellows interiorly in open communication withthe first tank fluid upstream of its control valve and having a free endoperatively connected to one side of the valve member. The valve meansmay further include an aneroid, second bellows having a free endoperatively connected to the valve member opposite the fluid receivingbellows for urging the valve member cooperatively with the lastmentioned bellows.

In preferred embodiments, the second tank fluid delivery controlincludes valve means responsive to a predetermined ratio of second tankpressure to first tank pressure to permit second tank discharge, meanscommunicating to one side of the valve member a force proportional tothe first tank pressure and means communicating to the opposite side ofthe valve member a force proportional to the second tank pressure; theforces being differently proportional to their respective tank pressuresin the ratio predetermined for operating the valve member. The forcecommunicating means in these embodiments may include the above-describedfluid receiving bellows having a predetermined effective diameter equalto the effective seat diameter of the opening controlled by the valvemember, proportioning the force on the valve member from first tankfluid pressure, and a surface on the opposite side of the valve memberin open communication with the second tank fluid and having apredetermined effective surface area proportioning the force from secondtank fluid pressure on the valve member opposite side. The ratio of thebellows effective area to the valve member effective surface area thusdefining the predetermined pressure ratio which actuates the valvemember. In this embodiment, an aneroid bellows may be provided asabove-described to bias the valve member cooperatively with the fluidreceiving bellows.

There may also be included means releasably blocking return movement ofthe valve member following second tank discharge into the line.

In a fluid delivery system for aircraft Windshields, a conduit to thewindshield is provided as the discharge line into which the fluid isdelivered from the first and second tanks, controlled as describedabove.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be furtherdescribed as to an illustrative embodiment with reference to theattached drawings wherein:

FIG. 1 is a schematic view of a fluid delivery system;

FIG. 2 is an enlarged detail view of a second tank fluid flow controlvalve responsive to a predetermined ratio of second tank to first tankpressure according to the invention; and

FIG. 3 is a view of the control valve locking pin taken along line 3-3in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a fluid deliverysystem is shown including fluid utilization device 1. Device 1 isrepresentative of devices requiring for operation periodic delivery offluid under pressure, e.g., a nozzle for application to a windshield ofrain repellent fluid. The device 1 is connected to a supply of fluide.g., rain repellent fluid, under pressure, contained in tanks 2 and 3.The fluid in tank 2 is denominated Supply No. 1 since it is firstdelivered to the device 1; the fluid in tank 3, Supply No. 2. Tanks 2and 3 are arranged to empty into conduit forming a discharge line 4 fordelivery to device 1. An on-olf control is provided across the dischargeline 4 including valve 5 and solenoid control 5a for the valve.

Tank 2 communicates with discharge line 4 through line 6 provided with acheck valve 7 against reverse flow into the tank. Line 8 communicatesfluid from line 6, upstream of the valve 7 to tank 3 fluid flow controlvalve 9, providing a pilot pressure in the valve 9 for purposes toappear.

Tank 3 communicates with discharge line 4 through line 10, valve 9 andline 11 so that the valve controls fluid flow from tank 3 to thedischarge line. In FIG. 1, the valve 9 is shown closed so that fluiddemand at device 1 is supplied from Supply No. l in tank 2. The presentinvention provides means for substituting Supply No. 2 fluid for SupplyNo. l fluid in a predetermined manner responsive to the ratio ofpressure in tank 3 to pressure in tank 2 and independent of pressure indischarge line 4, through the operation of valve 9.

With reference now to FIG. 2, the valve 9 is shown in detail.Structurally the valve 9 is seen to comprise a block 12 having a centralvertical bore 13 and terminating upwardly in a threaded neck portion 14.The bore 13 has an enlarged intermediate portion forming a valve chamber15 having a valve opening 16 surrounded by annular beveled valve seat17. Pilot pressure fluid from line 8 enters the block 12 at neck portion14. Line 8 is threaded into adapter 19 which is threaded onto the blockneck portion 14. Supply No. 2 fluid line 10 enters the block 12 at fluidinlet port 20 laterally of the bore 13 and below the valve chamber 15secured there by adapter 21 threaded into the port. Passage 22 leadsfrom fluid inlet port 20 to the lower extent 23 of the bore 13 below thevalve chamber 15. Supply No. 2 fluid exits from the block 12 at fluidoutlet port 24 into line 11 secured to the outlet port by adapter 25.The fluid outlet port 24 is disposed laterally of the bore 13 andcommunicates with valve chamber 15 through passage 26 leading downwardlythrough the block 12 from the valve chamber to the fluid outlet port.

Valve body 27, shown in open position in FIG. 2, is provided in thevalve chamber 15 to control fluid communication between the inlet andoutlet ports 20, 24. The valve body 27 comprises a generally conicalupper section 28 shaped and sized to engage the valve seat 17intermediate the upper section ends and carrying a sealing ring 30 and alower ring section 31 slidably received in lower bore extent 23 to guidethe valve body movement vertically. Sealing ring 30 engages the valveseat along line 30a which is equal in diameter, D to the effectivediameter, D,,, of upper bellows 43, as will be explained below. Valvebody 27 further includes an intermediate reduced diameter section 32between the valve upper and lower sections 28 and 31 respectively, andopposite passage 22 defining with lower bore extent 23 an annularchamber 33.

The valve body 27 is subject to upward force by virtue of the presenceof pressurized Supply No. 2 fluid in chamber 33. The force isproportioned by the net effective area A of the conical surface 29 actedon by the fluid below the valve sealing line 30a as will be described. Adownward force on valve body 27 is provided by the provision of aneroidbellows 36 within the bore lower extent 23 and below the valve lowersection 31. This bellows interiorly is at hard vacuum and accordinglyseeks to contract under external pressure. The bellows free end 37 issecured to the valve lower portion 31 by any convenient means; Theopposite end of the bellows 36 is adjustably fixed relative to the borelower extent 23 by the head of tee-fitting 38 into which screw 39 isthreaded through retaining ring 40 and retainer 41. The tee-fitting 38head is sealed with the bore lower extent 23 by suitable O-ring seal 42.

The valve body 27 is subjected to a principal downward force exerted bypressurized fluid from Supply No. l. Fluid from tank 3 (Supply No. l) ispassed into the valve block 12 through line 8 to exert a force on valvebody 27 as follows: A fluid-receiving bellows 43 is mounted in upperbore extent 44 with its fixed end fitting 45 clamped between adapter 19and the top of block neck portion 14 with appropriate sealing by ring46. A bellows free end fitting 47 suitably cup-shaped as shown, forpurposes to appear, and carrying actuating rod 48 closes the oppositeend of the bellows 43. Actuating rod 48 is secured to valve body uppersection 28 to transmit axial movement of bellows 43 to the valve body27. Bellows 43 calibration for particular devices is provided byadjustment screw 49 carried by bushing 50 in fixed end fitting 45 to actagainst spring retainer 52 and thus adjustment spring 53 set in cuplikefree end fitting 47. Bushing 50 is ported at 54 to permit fluid pressuresensing within the bellows 43.

The effective diameter D, of bellows 43 will determine the force appliedto valve body 27 by this bellows at a given fluid pressure at Supply No.l, in tank 2. The smaller the diameter of bellows 43 the less theeffective area of fluid pressure application and thus the smaller theforce on the valve body 27, and conversely an increased effective areafor the bellows 43 will increase downward force on the valve body for agiven Supply No. l fluid pressure. The downward force derived from fluidpressure in tank 2 may thus be proportioned by appropriate control ofbellows 43 effective area. The upward force on the valve body 27 derivedfrom Supply No. 2 fluid pressure may be proportioned by appropriatedimensioning of the conical surface portion 34 below the valve seatingring 30 to define a desired effective area A. Efi'ective area A isdefined by the difference between aneroid bellows 36 diameter D, andpilot pressure bellows 43 diameter D,,, thus,

In preferred embodiments, the sealing line 30a diameter D,

equals D so Accordingly, surface portion 34 lying between the concentriccylindrical figures having diameters D,,=D,, and D will have aneffective area of A. With the effective area of the fluid receivingbellows 43 equal to the effective area of valve seat 17, a circle seenin FIG. 2 as sealing line 30a, the upward force of the back pressure offluid in line 4 tending to compress bellows 43 is exactly equal todownward force of the line 4 fluid back pressure acting on the top ofvalve body 27 tending to compress bellows 36 so that these forces cancelout and back pressure variations in line 4 do not affect the valve 9operation.

The valve body 27 is subjected to forces derived from fluid pressure inSupply No. l and Supply No. 2 simultaneously and oppositely. A greaterupward force will displace the valve body 27 and thus open the valve tofluid flow from tank 3 (Supply No. 3). This will cause a rise in thefluid back pressure in discharge line 4 and thus cause check valve 7 inline 6 to close, whenever the fluid pressure in tank 2 is exceeded.

While the valve 9 may be designed to open whenever the pressure inSupply No. 2 exceeds the pressure in Supply No. l, the valve 9 asdepicted is adapted to operate at predetennined pressure ratios withoutregard to the absolute pressure in tank 3 to the fluid pressure in tank2 is 1.9 or any other ratio value. This is highly useful where twopressurized tanks are-to be used. Fluid supply from the first tank iscontinued until the first tank pressure falls below the second tankpressure in a certain ratio predetermined by the forces which the valvebody in the valve is subjected. That is, the downward force isproportioned to its fluid supply (No. 1) pressure and the upward forceis proportioned to its fluid supply (No. 2) pressure by the arrangementof valve ports with the upward and downward forces being differentlyproportioned to produce a ratio of forces on the valve body of somepreselected value.

In general, where x is a given ratio of inlet port pressure to pilotpressures to be maintained i.e., x=P /P,, the ratio of diameters may bederived from the expression D,/D, =x /(xl) where D, is the eflectivediameter of the pilot pressure reference bellows and is equal to D, theeffective valve seat diameter, and D, is the effective diameter of theaneroid bellows. For example, in an apparatus having a valve 9 as shownin FIG. 2, tanks 2 and 3 each initially having a fluid pressure ofp.s.i.a., F, is thesealing force in pounds on the valve body 27 and P,is the pressure in aneroid bellows 36 (=0 p.s.i.a.), then the conditionat which the valve 9 starts to open (sealing force, F ,=0) isrepresented by the equation from which it may be determined that for thevalve 9 to open at a pressure ratio of P, to P, of e.g., l.9 the ratioof the reference effective diameters D,, to D is !\/1 9/ 9 ==l.45 andthat under these conditions the valve 9 will open whenever the ratio ofSupply No. 2 pressure to Supply No. 1 pressure is 1.9 e.g., 125 p.s.i.a.to 65.8 p.s.i.a. or 30 p.s.i.a. to 15.8 p.s.i.a. and always at the sameratio through out the pressure range.

When opened, the valve body 27 may be locked in position to require amanual reset. Thus reset pin 56 is provided sealed with O-rings 57 intransverse bore 58 through the block 12. Reset pin 56 is biased leftwardby return spring 59 supported by annular rib 60 having a central vent 61covered by vent screen 62 held in the bore by staked washer 63. Whenvalve body 27 is in closed position, reset pin 56 is in its extremeright position with pin shoulder 64 engaging cooperating shoulder 65 onfree end fitting 47 of the bellows 43. When this fitting 47 lifts withvalve body 27, the reset pin 56 is pushed leftward by spring 59 as thepin shoulder 64 clears under the fitting. A stop 51 in groove 66 of pin56 limits leftward movement of the pin with the pin shoulder 64 inlooking engagement under fitting 47 (FIGS. 2, 3) against return movementof the fitting and thus closing movement of the valve body 27 into thevalve opening 16 until projecting tab 67 of the reset pin is manuallypushed to reset the valve.

1 claim:

1. System for the delivery of rain repelling fluid onto an aircraftwindshield including:

a. conduit leading onto said windshield.

b. a first tank of fluid under pressure for delivery to said conduit.

c. a second tank of fluid under pressure for delivery to said conduit.

d. a valve to control first tank delivery to said conduit and adapted toclose when conduit pressure is greater than the first tank pressure tocutoff first tank delivery to the conduit,

valve means including a valve member responsive to first tank pressureand second tank pressure to control second tank delivery to saidconduit,

f. a fluid receiving bellows interiorly in open communication with firsttank fluid and having a free end operatively connected to one side ofsaid valve member to communicate first tank fluid pressure to said valvemember, and

g. means communicating second tank fluid pressure to the opposite sideof said valve member whereby said valve member responds to second tankfluid pressure relatively higher than first tank fluid pressure topermit second tank delivery to said conduit.

2. Fluid delivery system according to claim 1, including also a secondbellows having a free end operatively connected to said valve memberopposite said fluid receiving bellows for urging the valve membercooperatively with said fluid receiving bellows.

3. Fluid delivery system according to claim 1, in which means (f) and(g) are arranged to operate said valve means responsive to apredetermined ratio of second tank pressure to first tank pressure.

4. Fluid delivery system according to claim 3, in which said bellowsmeans (f) communicates a force proportional to the first tank pressureto one side of said valve member and means (g) communicates a forceproportional to the second tank pressure to the opposite side of saidvalve member, said forces being differently proportional to theirrespective tank pres sures.

5. Fluid delivery system according to claim 4 including also meansreleasably blocking return movement of the valve member following secondtank discharge into the line.

6. Fluid delivery system according to claim 4, in which said fluidreceiving bellows has a predetermined effective area proportioning theforce on said valve member from said first tank fluid pressure, and saidvalve member has a surface on its opposite side in open communicationwith second tank fluid, said surface having a predetermined effectivearea proportioning the force on said valve member opposite side fromsaid second tank fluid pressure, the ratio of said bellows effectivearea to said valve member effective surface area defining saidpredetermined pressure ratio.

7. Fluid delivery system according to claim 6, in which the effectivediameter of said fluid receiving bellows is equal to the effective seatdiameter of the valve opening.

8. Fluid delivery system according to claim 6, including also aneroidbellows having a free end connected to said opposite side of the valvemember and operative to bias said valve member cooperatively with saidfluid receiving bellows against the proportioned force of second tankfluid pressure on said valve member.

1. System for the delivery of rain repelling fluid onto an aircraftwindshield including: a. conduit leading onto said windshield. b. afirst tank of fluid under pressure for delivery to said conduit. c. asecond tank of fluid under pressure for delivery to said conduit. d. avalve to control first tank delivery to said conduit and adapted toclose when conduit pressure is greater than the first tank pressure tocutoff first tank delivery to the conduit, e. valve means including avalve member responsive to first tank pressure and second tank pressureto control second tank delivery to said conduit, f. a fluid receivingbellows interiorly in open communication with first tank fluid andhaving a free end operatively connected to one side of said valve memberto communicate first tank fluid pressure to said valve member, and g.means communicating second tank fluid pressure to the opposite side ofsaid valve member whereby said valve member responds to second tankfluid pressure relatively higher than first tank fluid pressure topermit second tank delivery to said conduit.
 2. Fluid delivery systemaccording to claim 1, including also a second bellows having a free endoperatively connected to said valve member opposite said fluid receivingbellows for urging the valve member cooperatively with said fluidreceiving bellows.
 3. Fluid delivery system according to claim 1, inwhich means (f) and (g) are arranged to operate said valve meansresponsive to a predetermined ratio of second tank pressure to firsttank pressure.
 4. Fluid delivery system according to claim 3, in whichsaid bellows means (f) communicates a force proportional to the firsttank pressure to one side of said valve member and means (g)communicates a force proportional to the second tank pressure to theopposite side of said valve member, said forces being differentlyproportional to their respective tank pressures.
 5. Fluid deliverysystem according to claim 4 including also means releasably blockingreturn movement of the valve member following second tank discharge intothe line.
 6. Fluid delivery system according to claim 4, in which saidfluid receiving bellows has a predetermined effective area proportioningthe force on said valve member from said first tank fluid pressure, andsaid valve member has a surface on its opposite side in opencommunication with second tank fluid, said surface having apredetermined effective area proportioning the force on said valvemember opposite side from said second tank fluid pressure, the ratio ofsaid bellows effective area to said valve member effective surface areadefining said predetermined pressure ratio.
 7. Fluid delivery systemaccording to claim 6, in which the effective diameter of said fluidreceiving bellows is equal to the effective seat diameter of the valveopening.
 8. Fluid delivery system according to claim 6, including alsoaneroid bellows having a free end connected to said opposite side of thevalve member and operative to bias said valve member cooperatively withsaid fluid receiving bellows against the proportioned force of secondtank fluid pressure on said valve member.